DGP Cosmological model with generalized Ricci dark energy

TL;DR

This paper investigates a DGP braneworld cosmological model with a holographic Ricci-like dark energy component, analyzing its theoretical behavior and fitting it to supernova data, but finding it less favored than the standard Lambda-CDM model.

Contribution

It introduces a holographic Ricci-like dark energy in the DGP model, providing analytical solutions and observational constraints for the model parameters.

Findings

The model fits supernova data well.

Most likely parameter values are identified.

The model is disfavored compared to Lambda-CDM based on BIC.

Abstract

The braneworld model proposed by Dvali, Gabadadze and Porrati (DGP) leads to an accelerated universe without cosmological constant or other form of dark energy for the positive branch $(\epsilon =+1)$. For the negative branch $(\epsilon =-1)$ we have investigated the behavior of a model with an holographic Ricci-like dark energy and dark matter, where the IR cutoff takes the form $\alpha H^2 + \beta \dot{H}$, being $H$ the Hubble parameter and $\alpha$, $\beta$ positive constants of the model. We perform an analytical study of the model in the late-time dark energy dominated epoch, where we obtain a solution for $r_cH(z)$, where $r_c$ is the leakage scale of gravity into the bulk, and conditions for the negative branch on the holographic parameters $\alpha$ and $\beta$, in order to hold the conditions of weak energy and accelerated universe. On the other hand, we compare the model versus the late-time cosmological data using the latest type Ia supernova sample of the Joint Light-curve Analysis (JLA), in order to constraint the holographic parameters in the negative branch, as well as $r_cH_0$ in the positive branch, where $H_0$ is the Hubble constant. We find that the model has a good fit to the data and that the most likely values for $(r_cH_0, \alpha, \beta)$ lie in the permitted region found from an analytical solution in a dark energy dominated universe. We give a justification to use holographic cut-off in 4D for the dark energy in the 5 dimensional DGP model. Finally, using the Bayesian Information Criterion we find that this model it is disfavored compared with the flat $\Lambda$CDM model.